Even though projectile speed helps, it's not the same as firing from 3K unless your cursor is dead on with zero error.
But that sounds like quite a big speed up. Maybe a bit less would be more in line.
If you get double the range, you get double the speed, and this cuts the amount you have to lead by half, which reduces the square area of your potential margin of error by four fold, and the volume by eight fold.
These are two huge long range phasing PA's spun for ~1600m/s projectile velocity (same as a stock huge MC round)...could have gone for more, but that would have taken a prohibitive number of rolls to synchronize two PA effectively:
[video=youtube;ke-W5IXZItM]https://www.youtube.com/watch?v=ke-W5IXZItM[/video]
My aim is total crap as I had just come back from a 6 month break the day before this video was recorded and have only recently focused on PAs (because of the changes to them), but you can clearly see how much the improved project velocity helps. Not shown here, but also I did get a few 5-6km single shot kills on unsuspecting NPCs or those fleeing in straight lines.
Now, I wouldn't choose long range over efficient on most ships, but the large (DPE and damage vs. mass is far better than huge) PA that's going on the bottom of the lightweight FDL interceptor I'm making is going to be long range (and probably phasing).